Studies on unsteady operation of a turbojet engine and an intake channel of a supersonic aircraft

• Autorzy: Kowalski M. , Szczepanik R.

Identyfikatory

DOI

10.5604/12314005.1133888

• Języki publikacji: EN

Abstrakty

EN

The paper explains how to analyse possible disturbances in the intake air stream and their impact on engine operation. The introduction outlines possible reasons that induce disorders in the intake air stream. Then the substantial differences in operational characteristics between a centrifugal and an axial compressor are enlightened. The phenomenon of an unsteady compressor, referred to as the compressor stall, is explained through presentation of the process phases when air stream detaches from the surfaces of the compressor blades. Then the paper presents how disturbances in the air stream propagate down subsequent stages of the engine compressor with the emphasis on the fact that the air stream is not able to affect the full height of blades but usually only a portion of them. In addition, the mechanism of the unsteady operation of the engine (compressor) is presented on the graph that shows fuel consumption Q as a function of the engine rpm n. Attention is drawn to the fact that the phenomenon of the engine unsteady operation is associated with the so called rotating areas of air detachments that revolute in the same direction as the engine rotor itself but their rotation speed is lower than the rotor rpm. Consequently, flame downstream the area of detachment may go out for a moment and then quickly reappear, since air is kept supplied at quite high rates. If the foregoing process fails to go in phase with the rotating areas of air detachment, it may even lead to a total flameout of the engine. Then the unsteady operation of the intake channel is discussed in details, as it is frequently mismatched with the compressor stall. The mechanism of the phenomenon origination and the consequences it entails is presented with adequate details by means of appropriated graphs. In addition, the paper explains the phenomenon of beats in the intake channel, which is a result of detachment of the wall-adjacent layer of air flow just downstream the perpendicular shock wave in the intake channel. The effect of beats frequency often leads to the engine stall. The paper ends up with conclusions, in which it is emphasized that studies on the phenomenon and familiarity with the process are extremely important for the safety of flights.

Słowa kluczowe

EN

stall in the intake channel

• Wydawca: Łukasiewicz Research Network - Institute of Aviation ; European Science Society of Powertrain and Transport KONES Poland ; Wydawnictwo Instytutu Technicznego Wojsk Lotniczych
• Czasopismo: Journal of KONES
• Rocznik: 2014
• Tom: Vol. 21, No. 2
• Strony: 143--151
• Opis fizyczny: Bibliogr. 12 poz., rys.

Twórcy

autor

Kowalski M.

• Air Force Institute of Technology Księciai Bolesława Street 6, 01-494 Warsaw, Poland tel: [phone], fax: [phone]

autor

Szczepanik R.

• Air Force Institute of Technology Księciai Bolesława Street 6, 01-494 Warsaw, Poland tel: [phone], fax: [phone]

Bibliografia

• [1] Balicki, W., Chachurski, R., Kawalec, K., Kozakiewicz, A., Szczeciński, S., Unsteady operation of turbojet engines – reasons of occurrence and preventive precautions, Transactions of the Institute of Aviation, Scientific quarterly, 4, (199), Warszawa 2009.
• [2] Dzierżanowski, P., Kordziński, W., Łyżwiński, M., Otyś, J., Szczeciński, A., Wiatrck, R., Turbojet engines, WKŁ Edition House, Warsaw 1983
• [3] Kowalski, M., Issues related to troubleshooting of turbojet avionic engines with use of information from on-board recorders of flight parameters, ITWL Scientific Journals, No. 31, Warsaw 2013.
• [4] Kowalski, M., Adaptive Jet Engines Work Analysis and Control, Journal of KONES Powertrain and Transport, Vol. 18, No. 2, pp. 225-234,2011.
• [5] Kowalski, M., Noise Emission Level versus the Structure of the Aircraft Turbine Engine,Journal of KONES Powertrain and Transport. Vol. 19, No. 4, pp. 325-332,2012
• [6] Kowalski, M., Odwzorowanie fazowe prędkości obrotowej w procesie eksploatacjiturbinowych silników odrzutowych. Logistyka nr 6/2009. (Phase imaging of rotation speed during the operation of turbojet engines. Logistics, No. 6/2009).
• [7] Kowalski, M., Use of Data From on-Board Data Recorders far Acceptance Tests of Avionic Driving Units, Journal of KONES Powertrain and Transport, Vol. 20, No. 2 , pp. 201-206,2013.
• [8] Kozakiewicz, A., Kowalski, M., Unstable operation of the turbine aircraft engine. Journal of Theoretical and Applied Mechanics, Vol. 51, No. 3, pp. 719-727, 2013.
• [9] Szczeciński, S., Air intakes of turbojet avionic engines and meir effect on flying characteristics ofaircrafts and liazards to safety of flights. Issues of avionic driving systems. Transactions of the Institute of Aviation, No. 4, 2009.
• [10] Szczepanik, R., Investigation of the Dynamic Properties of Engine Fan Titanium Rotor Blades in a High Manoeuvrability Aircraft in FDD Aspect, Journal of KONES Powertrain and Transport, Vol. 20, No. 2, pp. 371-376, 2013
• [11] Szczepanik, R., Collaboration between a jet engine and its supersonic inlet at the end of the nosediving operation, Safety of flights, Warsaw 1979.
• [12] Wiatrek, R., Theory of avionic engines, Military Institute of Technology (WAT), Warsaw 1983.